这段代码为什么不输出啊？

#include<cstdio>
using namespace std;
int main(){
	int n1,n2;
	scanf("%d",&n1);
	scanf("%d",&n2);
	int a[n1+1];
	int x[n2+1];
	for(int i=0;i<n1;i++){
		scanf("%d",&a[i]);
	}
	
	for(int i=0;i<n2;i++){
		scanf("%d",&x[i]);
	}
	int b=n1-1,s=0,q;
	for(int i=0;i<n2;i++){
		for(int j=0;j<n1;j++){
			q=(b+s)/2;
			if(a[q]>x[i]){
				a[q]=b;
			}else if(a[q]<x[i]){
				a[q]=s;
			}else if(a[q]==x[i]&&a[q-1]!=a[q]){
				printf("%d ",a[q]);
				break;
			}else{
				printf("-1");
				break;
			}
		}
	}
	return 0;
}